Kawasaki Ki-91

The designation Kawasaki Ki-91 was given to a design for a four-engined heavy bomber under development in Japan between 1943 and 1945. It was to be powered by four 2,500hp Mitsubishi Ha-214 Ru engines, and have a pressurized cabin. It would have been very heavily armed, carrying twelve 20mm cannon, four in a tail turret and the remaining eight in four twin turrets - one in the nose, one dorsal turret and two ventral turrets. The Ki-91 would have been larger than the Boeing B-29 Superfortress, and with a much wider radius of action, but only half of the bomb load.

Work began on the design in May 1943, and by the end of 1944 a prototype was under construction as were the tools needed for full scale production. In February 1945 the tooling was destroyed during a B-29 raid, and work on the project was suspended.